Process for the decoration of ceramics



Patented Dec. 23,1047

. 3 PROCESS FOR THE DECORATION OF a... nomads-seminarians London.England, assignors to Johnson. Matthey & Company Limited,

British company No Drawing.

iieation London. England. a

November to, 104:.

MP r1'l9a4lzN0. 512,354. In GrentBrltaln Deeem Claims. (01. 41-83) Thisinvention relates to the production of transfer paper suitable forprinting ceramic or other transfers. Such transfer paper usuallyconsists of a sheet of porous gummed backing paper to the gummed side ofwhich there is applied a transparent film of cellulose acetate,cellulose nitrate or the like which may also contain a'plasticiser. Toobtain the optimum result it is essential that the said film should havea uniform predetermined thickness. The film material, such as cellulosenitrate or cellulose acetate, is usually applied to the gummed backing Pp r in the form of a solution, for example in acetone, by means of acoating machine and a uniform predetermined thickness is secured byregulating the viscosity of the solution and by making mechanicaladjustments in the coating machine. Since the paper is white and theplastic film is transparent, it is impossible to observe any differencesin film thickness by visual inspection and the machinery must thereforebe stopped from timetotime to determine the film thickness by actualmeasurement. It is still possible, however, for local diii'erences infilm thickness to occur.

According to the present invention these difiiculties are overcome byusing for the preparation of the film on a transfer paper a coatingsolution comprising a transparent colouring material which is soluble inthe solvents used. Organic dyes are very suitable and as examples wemention Malachite Green, Rose Bengal and Methyl Violet, all of which areeasily soluble in acetone.

Suitable coatlngsolutions are as follows:.

- l Parts Cellulose acetate 10 Diethyl phthalate 3 Acetone 100 MalachiteGreen 0.01

Parts Cellulose nitrate 10 Acetone 100 'Rose Bengal 0.02

. Parts Cellulose acetate l0 Diethyl phthalate 3 Acetone 100 MethylViolet 0.006 Malachite Green 0.004

By theme of a coloured coating solution it is possible to observe byvisual inspection any varia- I 2 'tions in the thickness of theresulting film. Such variations will be revealed by a difference in thecolour of the film and adjustments may be made without stopping thecoating machinery. Variations in the thickness of the film after dryingare shown by irregularities in the depth of the colour and it istherefore possible to cut out and discard those portions of thepaper'which have an unsatisfactory film, thus efiecting an appreciableeconomy in the number of transfers rejected after the colour design hasbeen printed on the film.

Another advantage of the use of a coloured film is that it is frequentlynecessary to have a white background colour in the transfer design andany faults in the printing or registration of the white part of thedesign are much more readilyshown up when the design is printed on acoloured background than when it is printed on a white paper coated witha transparent colourless film.

While we prefer a bluish-grey tint similar to that given by the mixture(3) above, the colour of the colouring material used in the processaccording to this invention is not important, The colouring materialmust, of course, be soluble in the coating solution and also, in thecase of ceramic transfers, must burn oi! during the subsequent firingoperation without leaving any residue.

What we claim is:

1. A process for the decoration of a ceramic with a design of a materialwhich will not burn on firing, which consists in applying to the gummedside of a summed backing p r a n transparent coloured film comprising awater insoluble cellulose ester selected from the group consisting ofcellulose nitrate and cellulose acetate.

and an organic dye, which film will burn away on firing; applying saiddesign to said film; and

. transferring said coloured film with the design thereon to aceramic.

2. Aproc'ess for the decoration of a ceramic with a design of a materialwhich will not burn on firing, whichconsists in applying to the gummedside of a summed backing paper a thin coating of a solution in anorganic solvent of a water insoluble cellulose ester selected from thegroup consisting of cellulose nitrate and cellulose acetate, and anorganic dye; allow'ingthe solvent to evaporate to produce on said papera thin transparent coloured 'film which will burn away on firing;vapplyin g said design to said film; and

transferring a ceramic. V

3. A process-as claimed in claim 1 wherein the organic dye consists ofMalachite Green.

d film with the design thereon to 3 4. A process as claimed in claim 1wherein the organic dye consists of Rose Bengal.

5. A process as claimed in claim 1 wherein the organic dye consists ofMethyl Violet.

ERNEST ROBERT BOX. FRANK ENOCH ,KERRIDGE.

REFERENCES CITED Number Number UNITED STATES PATENTS Name Date Reese May3, 192'! Laws Oct. 28, 1930 Dow June 12, 1934 MacLaurin Aug. 30, 1938Kaber Feb. 13, 1940 FOREIGN PATENTS Country Date Great Britain Aug. 31,1937

